Process of electrolyzing soluble salts.



NTTE'D STATES PATENT OFFICE.

ANTOINE JOSEPH OUTHENTN CHALANDRE AND LOUIS JEAN BAPTISTE AU- GUSTINCOLAS, OF PARIS, AND CHARLES JULES GERARD, OF SEVEUX,

FRANCE.

PROCESS OF ELECTROLYZING SOLUBLE SALTS.

SPECIFICATION forming part of Letters Patent No. 665,953, dated January15, 1901.

Original application filed March 21, 1899, Serial No. 709,939. Dividedand this application filed A il 16, 1900. Serial No. 13,282. (Nospecimens.)

T m7] whowt it may concern:

Be it known that we, ANTOINE JOSEPH OU- THENIN CHALANDRE and LoUIs JEANBAP- TISTE AUGUSTIN CoLAs, residents of the city of Paris, and CHARLES JULES GERARD, a resident of Seveux, in the Republic of France,haveinvented a new and useful Improvement in Processes for ElectrolyzingSoluble Salts, which invention is fully set forth in the fol- IO lowingspecification.

This application is a division from our application filed March 21,1899, Serial No. 709,939, (Patent No. 647,217, dated April 10, 1900,)which shows apparatus suitable for carrying out the process hereindescribed and claimed.

As an example-of the application of our process which may be employedfor electrolyzing all soluble salts we will describe the same hereinwith reference to chlorid of sodium, the object being to obtain sodiumhydroXid on the one hand and pure chlorin gas on the other hand inquantities substantially the same, as these products are combined in thechlorid of sodium, or, in other words, without loss of sodium hydroxidor chlorin by reason of the electrolytic action.

It is well known that in the electrolyzation of chlorid of sodium theelectric current will have the effect of forming, first, at the cathode(ct) a solution of caustic soda produced by the sodium of the saltcombining with hydroxyl which is furnished by the water of theelectrolyte, while the corresponding hydrogen 5 is set free, and (b) theliberationof hydrogen in consequence of the decomposition of part of theWater of the electrolyte, and, second, at the anode (c) the liberationof chlorin caused by the decomposition of the salt, (d) the liberationof oxygen corresponding to the hydrogen liberated, as stated in (b). Itwill be seen, therefore, that there takes place in particular aliberation of chlorin and of hydrogen.

Under the ordinary conditions of operation the chlorin-oxygen compounds,generally in the form of hypochlorous acid, which form in the apparatusact to greatly diminish the output of chlorin, and, furthermore, it isnecessary under these conditions to maintain a low temperature, so as toprevent the trans- 5o formation of the hypochlorous acid into chlorate.It is known that at about 45 centi grade hypochlorous acid becomeschanged into chloricacid and from this, in presence of sodium hydroxid,into chlorate. Hence to avoid this transformation it is necessary toadvance with a comparatively low temperature, under which conditions theresistance of the bath is great and the amount of the product small.

The object of the present invention is to completely recuperate thechlorin issuing at the anode while destroying the oxygen compounds ofthe chlorin, and in this manner to obtain the maximum yield of chlorin.

To this end the invention consists in combining a part of the chlorinissuing at the anode with the hydrogen released at the cath-. ode toform hydrochloric acid, which is then introduced into the apparatus tobreak up the chlorin-oxygen compounds which form therein. Thecombination of the chlorin and hydrogen to form hydrochloric acid may beeffected by burning the hydrogen in contact with the chlorin in themanner set forth in our above-mentioned patent. As soon as thehydrochloric acid comes into contact with the anodic liquid thechlorin-oxygen compound is decomposed in accordance with the followingequation:

It is to be understood that the hydrochloric acid is produced inquantityjust suficient to effect this decomposition. If too much isformed, the excessive amount would accumulate in the apparatus and bedetrimental to the operation, while diminishing the production ofchlorin, part of which would remain in the apparatus in the accumulatedhydro- 9o chloric acid. It will therefore be seen that all of thechlorin is recuperated, even that which has been momentarily convertedinto hydrochloric acid for the purpose above indicated, the hydrochloricacid existing only 5 from the point of its formation outside of theapparatus to the point of its introduction into the same, none of itaccumulating thereon.

An important feature of the process is the continuity of its cycle andthe use of hydrochloric acid formed from the hydrogen and chlorinliberated from the electrolyte itself, no other reagents being employed.

The regulation of the flame of the burner, and consequently the quantityof hydrochloric acid which itis expedient to form momentarily and toreintroduce into the apparatus, varies essentially first, according tothe nature of the electrolyte, and, secondly, according to the alkaliconcentration adopted as a regulating measure at the cathode-compart-,

ment. For example, in the case of the electrolysis of sodium chloridaccording to the caustic-soda concentration at the cathode adopted as areguiating measure the quantity of hydrochloric acid which ismomentarily formed may vary practically from about five to forty percent. of the equivalent quantity of caustic soda produced in the samespace of'time.

What we claim is 1. The herein-described process of electrolyzing asoluble saltthe electrolyzation of which causes detrimental secondaryreactions in the electrolyzer, and which salt is capable of yielding atthe anode and cathode gases which when combined form an acid, saidprocess consisting in passing an electriccurrent cathode, combiningoutside of the apparatus diuin for the purpose set forth, consisting inpassing an electric current therethrough from an anode to a cathode,combining hydrogen liberated at the cathode with a portion of thechlorin liberated at the anode to form hydrochloric acid, thenintroducing the acid thus formed into the anode-compartment to decomposethe chlorin-oxygen compou nds which form therein and to liberate orrecuperate the chlorin evolved at the positive pole which has served inthe formation of the acid.

7 In testimony whereof we have signed this specification in the presenceof the subscribing witnesses.

ANTOINE JOSEPH OUTHENIN OHALANDRE. LOUIS JEAN BAPTISTE AUGUS'IIN COLAS.CHARLES JULES GERARD.

Witnesses as to A. J. O. O. and L. J. B. A. C.

' EDWARD P. MACLEAN,

EMILE LEOTOD. Witnesses as to O. J. G.: JULEs RoUssET, GEORGES CARRIERE.

